Figure 1 - uploaded by Ilze Beverte
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The structural units: pre-expanded polypropylene beads. a) N-9210 and b) N-9240 BSW (LM microphotographs).
Source publication
Neopolen® P is a two-phase cellular composite foam material produced by BASF AG, Germany. In most of the practical applications, Neopolen® P works under a range of small and compressive deformations. Therefore it is necessary to determine the moduli in compression and compressive strength in the most effective way for a wide range of foam densities...
Contexts in source publication
Context 1
... characteristic two level structure of Neopolen was revealed. The first level is formed by pre- expanded polypropylene beads (Figure 1) pressed together with the help of hot damp. As can be seen on REM photographs a definite portion of beads (different for each recipe) has a thin outer layer of monolith polymer. ...
Context 2
... structure of Neopolen was investigated both on light (LM) and raster-electron microscope (REM). The characteristic two level structure of Neopolen was revealed. The first level is formed by pre- expanded polypropylene beads (Figure 1) pressed together with the help of hot damp. As can be seen on REM photographs a definite portion of beads (different for each recipe) has a thin outer layer of monolith polymer. The second level is formed by nearly 100% closed cell isotropic foam inside the beads. As the volume of beads exceeds the characteristic volume of cells considerably (Figure 2), deformation theories [2] of homogeneous foams can be applied to the foam inside beads. Results of loose, before molding beads' dimensions' measurements according to photographs are presented in Table 1. The shape of beads varies between that of a cushion-type and that of an extended ellipsoid. For all series of the investigated loose beads one dimension (l y ) of a bead is bigger than the other two ones l x , l z : l y < l x , l z . l x , l y , l z are average dimensions obtained from measurements of 10 beads. That leads to existence of energetically favourable positions (positions of stabile equilibrium) of a bead with respect to the Earth gravitation direction, while pouring beads into the mold. Beads will tend to fall with the biggest dimension l y perpendicular to acceleration of gravity vector g, parallel to the Earth surface. Beads of recipes N-8210, N-9210 can be considered as having nearly equal dimensions. Such beads will provide nearly random spatial distribution of beads' dimensions in the ...
